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Home/Water Quality/Los Angeles County
Water quality testing site · Los Angeles County

Descanso Bay - end of beach

Tested by Los Angeles County, usually every 28 days.

A
Latest test · Tuesday, Oct 6, 2026
Water quality A: Clean

Taken 38 days ago. Results can take 1 to 3 weeks to be published, and many sites are tested less often in winter.

Enterococcus
under 10
per 100 mL
Safe limit
104
This test was 10% of the limit.
Usual here
10
The middle of 8 tests over the past year. This test is about normal for this beach.

Every bacteria in this test: Total coliform under 10 · E. coli under 10 · Enterococcus under 10. The grade follows the worst one against its own limit.

Can I go in?

No recent test

The last test here was 38 days ago, too long ago to say anything about the water today. Some sites are tested only in summer. Stay out for 72 hours after any rain of 0.2 in or more, and check the county's status before going in.

Yellow flag: bacteria advisory County status: Advisory, checked Friday, Nov 13 (Los Angeles County Department of Public Health). The county’s posting is the final word.

History

Enterococcus over time

10100Usual here: 10Safe limit: 104NovJan 2026MarMayJulSepNov
Rain of 0.2 in or more at the nearest airportsHover or tap a dot for its date and reading

No National Weather Service rain gauge is within 20 miles of this site.

Recent tests
  • A
    Tuesday, Oct 6, 2026
    Total coliform under 10 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, Sep 1, 2026
    Total coliform 20 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, Aug 11, 2026
    Total coliform 20 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, Jul 14, 2026
    Total coliform under 10 · E. coli under 10 · Enterococcus 10
  • A
    Tuesday, Jun 2, 2026
    Total coliform 10 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, May 12, 2026
    Total coliform under 10 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, Apr 7, 2026
    Total coliform 20 · E. coli under 10 · Enterococcus under 10
  • A
    Tuesday, Oct 21, 2025
    Fecal coliform under 10 · Total coliform 20 · Enterococcus under 10
  • A
    Tuesday, Aug 5, 2025
    Fecal coliform under 10 · Total coliform 10 · Enterococcus 20
  • B
    Tuesday, Jul 1, 2025
    Fecal coliform under 10 · Total coliform under 10 · Enterococcus 41
What the numbers mean

Enterococcus and coliform bacteria live in the guts of people and animals. Health departments test for them because they travel with sewage, runoff and animal waste, so a high count is a warning that germs that do make people sick are likely in the water too. Clear water can still be contaminated: bacteria and viruses are too small to see.

San Diego County's DNA test (ddPCR) counts bacterial DNA instead of growing the bacteria in a lab, so it returns results the same day. Its numbers run higher than the older lab tests, which is why its safe limit is 1,413 rather than 104. The two are never compared on this page.

San Diego County's health department says swimming in water under an advisory can cause stomach illness, such as diarrhea and vomiting, and skin and ear infections. The EPA's national swimming guidelines are set at a level where about 32 to 36 of every 1,000 swimmers would get a stomach illness. A study of San Diego surfers found about 12 extra stomach-illness cases per 1,000 in wet weather, highest during rain and the day after, and back near normal 3 days later.

The grade is Nautical Nick's, built on the official limits: A is a quarter of the limit or less, B half or less, C under the limit, D over it, and F more than 10 times over. When a county posts an advisory or closes a beach, its sign is the final word.

Sources: California State Water Board beach test results; San Diego County Department of Environmental Health sample reports; Surfrider Foundation Blue Water Task Force; National Weather Service daily rain totals via the Iowa Environmental Mesonet. Limits: California Code of Regulations, Title 17, Section 7958.